Apparatus for forming metal tubes



May 12, 1925#` *n l 1,537,207

` M. U. WKSTROM APPARATUS FOR FORMING METAL TUBES Filed Aug. 22, 1924 Patented May 12, 1925.

UNITED STATES MALCOLM U. WIKSTROM, F DETROIT, MICHIGAN. I

APPARATUS FORMING METAL TUBES.

Application filed August 22, 1924. Serial No. 733,586.

T o all t0/1.0m t may concern.'

Be. it known that I, MALCOLM U. W11;- s'rnoM, a citizen of the United States, and resident of Detroit, in the county of lVayne and State of Michigan, have invented a new and useful Improvement in Apparatus for Forming Metal Tubes; and I do hereby declare the following to be a full, clear, and

exact description thereof.

My invention relates to apparatus for forming tubes, and particularly to means for facilitating the handling of the plug or mandrel over which seamless tubes are rolled.

In my application, Serial No. 625,771, filed March 17, 1923, I have shown apparatus for utilizing a spherical plug or mandrel in forming seamless tubes. The present application constitutes an improvement in the means for manipulating such spherical plug.

Heretofore the practice has been, when employing plugs or mandrels of elongated form, to withdraw them from between the roll pass manually by tongs. In many cases two workmen were required to perform this service. In my application referred to above, provision is made for returning the spherical ball by a reverse movement of the tube upon completion of a pass. "Ihe object of mypresent invention is to provide means for automatically returning the ball or plug, thereby giving it a start ahead of the returning tube, so as to give the ball time to drop out of the way before the tube is returned.

One manner in which my invention may he practiced is shown inthe accompanying drawing wherein Fig.1 is a sectional eleva.- tional view showing a plug in operative position inthe roll pass, and Fig. 2 is a similar view showing the manner in which the plug is returned' to starting position.

'lhe rolls 3 may be of a form suitable for rolling tubes. A mandrel bar 4 is provided with a recessed portion which is closed by 'a head or seat portion 5 that has screw threaded engagement with the recessed portion of the mandrel. A compression spring 6 is contained within the recess of the mandrel bar 4 and seats against a collar 7 formed on a plunger 8 that extends through a longitudinal opening in the mandrel head 5. Instead of the s ring Aan air pressure can be employed which could be admitted through a hole 12 in the mandrel-bar 4:.

A tube 9 is fed between the rolls 3, over a mandrel or plug 10 that is held in position in the roll pass by the mandrel head 5, to expand the inside of the tube 9 as it m'oves between the rolls 3.

The plug 10 is advanced by reason of movement of the tube, from the position indicated in full lines in Fig. 2 to the position indicated in Fig. 1, thereby compressing the plunger 8 against the spring 6 so that when the tube 9 has advanced to the position indicated in Fig. 2, the plug 10 will be released therefrom and the spring 6 per-- `mitted to return the plug '10 to the guide trough 11, as indicated in dotted lines in Fig. 2.

Various detail changes may be made Without departing from the spirit and scope of the invention as defined in the accompanying claims.

I claim as my invention:

1. In apparatus for making tubing, the combination with rolls, of a mandre bar, a spherical plug engaging said bar in the pass of the rolls, and spring means stressed during advancing movement of said plug for returning said plug to a point in front of the rolls upon completion of a pass.

2. In apparatus for making seamless tub ing, the combination with rolls, of a mandrel bar, a spring pressed plunger normally protruding to the front of said bar, and a spherical plug adapted to engage said plunger'and bar when in the pass of the rolls.

3. In apparatus for making tubing, the combination with rolls, of a mandrel bar having a recess at its forward end, a spring within said recess, a plunger seating against said spring and vnormally projecting to the front of said bar, and a spherical plug adapted to depress said plunger and engage the front of the bar when in operative position in ,the pass of the rolls.

Il. The combination with rolls for form ing tubes, of a mandrel bar, a plug movable into the pass of the rolls, 'and resilient means placed under stress upon advance movement of said plug into said pass, for returning said plug to position.

In testimony whereof I, the said MAL- oom U. WIKsTRoM, have hereunto set my han MALCOLM U. WIKs'rRoM. 

